Wash potatoes and boil water for about 15 minutes. In the meantime wash and peel the cucumbers and cut them lengthwise. Remove seeds with a spoon and cut the halves into thick slices. Peel and finely chop the onion. Wash the dill, dab dry and cut finely, except for a little bit for garnishing.
Drain the potatoes, rinse under cold water and let them drain. Peel the skin off the potatoes. Heat the oil in a large pan and fry the potatoes until golden brown, turning them over. Season with salt and pepper and remove from the pan. Wipe out the pan. Heat 20 g fat in the pan and sauté the onions. Add braised cucumbers, fry and season with salt and pepper. Pour in broth, bring to the boil, cover and simmer for about 5 minutes. Heat 20 g fat in a layered pan and fry the frozen fish fingers for 5-8 minutes while turning. Mix crème fraîche, flour and mustard and stir into the stewed gherkin stock.
Add braised cucumbers, fry and season with salt and pepper. Pour in broth, bring to the boil, cover and simmer for about 5 minutes. Heat 20 g fat in a layered pan and fry the frozen fish fingers for 5-8 minutes while turning. Mix crème fraîche, flour and mustard and stir into the stewed gherkin stock. Add the potatoes and simmer again for another 2 minutes. Stir the dill, except for something to sprinkle, into the sauce and season to taste with salt, pepper and lemon juice. Place fish fingers on the pan-fried vegetables and serve garnished and sprinkled with lemon and dill